Floating tank



Dec. 11, 1962 E. H. DOERPINGHAUS 3,067,712

FLOATING TANK 5 Sheets-Sheet 1 Filed Sept. 18, 1957 IN VEN TOR.

Dec. 11, 1962 E. H. DOERPINGHAUS 3,06

FLOATING TANK Filed Sept. 18, 1957 5 Sheets-Sheet 2 INVENTOR.

Dec. 11, 1962 E. H. DOERPINGHAUS 3,067,712

' FLOATING TANK Filed Sept. 18, 1957 5 Sheets-Sheet 3 I: INVENTOR. Q0 Q2Aha/107N44 M Afr-W 7 Dec. 11, 1962 E. H. DOERPINGHAUS 3,067,712

FLOATING TANK 5 Sheets-Sheet 4 Filed Sept. 18, 1957 INVENTOR. D7NJM7AMh/z/wwl 1. 5

Dec; 11, 1962 E. H. DOERPINGHAUS 3,067,712

FLOATING max Filed Sept. 18, 1957 5 Sheets-Sheet 5 5 4 INVENTOR.

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The present invention relates to a floating tank for transporting liquidon water ways, and more particularly to a floating tank for transportingoil which is towed by a tugboat.

Transport of oil and other liquids, on Waterways, is generally carriedout by tankers. it is known to connect several tankers by cables and topull a train of tankers by tugboat. While the known tankers are loadedand unloaded, almost the entire machinery is unused, and consequentlythe operation is uneconomical. Another disadvantage of tankers residesin that almost the same machine power is needed for towing empty andfilled tankers, since the empty tankers have to be filled with ballast.Water is used as ballast which requires again additional pumps anddevices for cleaning the tanks be fore oil is filled into the same.

it is the object of the present invention to overcome the disadvantagesof known arrangements for transporting liquids on waterways, and toprovide a floating tank for transporting liquids in economical manner.

Another object of the present invention isto provide a floating tankwhich can be towed by a tugboat, and can be collapsed when not in use.

Another object of the present invention is to provide a floating tankwhich is light and flexible, but nevertheless seaworthy.

With these objects, and other objects which will appear as thedescription of the invention proceeds, the present invention mainlyconsists in a floating tank for transporting liquid on waterways andwhich is towed by a tugboat. The floating tank according to the presentinvention mainly comprises container means including a plurality ofclosed container cells having flexible Walls and adapted to be filledthrough an opening with the liquid to be transported.

Preferably, a flexible casing and a net means envelop the containercells. The walls of the container cells and of the casing are preferablymade of an artificial synthetic material and have an inner lining of agummy substance which tends to close leaks in the respective walls.

Gne of the container cells is filled with air, and has a safety valve sothat when the other liquid-filled cells are deformed by impact orpressure, the air-filled container cell is compressed and discharges airthrough the safety valve.

Since the container means roll in a heavy sea, a tow cable whichconnects the net means with the tugboat, is preferably provided with acoupling means including two relatively turnable coupling parts. Inorder to relieve the tow cable of extreme tensile forces, it iscontemplated to provide additional propelling and rudder means which areattached to the tank and help to propel the same. Such additionalpropelling and rudder means are particulariy advantageous if a train isformed of several floating tanks, and in this event, the propelling andrudder means are arranged between two floating tanks and connected tothe same by cables.

The novel featureswhich are considered as characteristic for theinvention are set forth in particular in the appended claims. Theinvention itself, however, both as to its construction and its method ofoperation, together with additional objects and advantages thereof, willbe best understood from the following description of specific gratesFatent ice embodiments when read in connection with the accom panyingdrawings, in which:

FIGURE 1 is a side elevation of a floating tank according to oneembodiment of the present invention;

FIGURE 2 is a side elevation of a train of two floating tanks accordingto the present invention;

FIG. 2a is a cross-sectional view of a cable enveloping the tank;

FIGURE 3 is a fragmentary plan view of a floating tank according to thepresent invention;

FIGURE 4 is a cross-sectional view of a floating tank according to thepresent invention taken on line 4-4 in FIG. 2;

FIG. 4a is a fragmentary longitudinal sectional view taken on line "4a4ain FIG. 4;

FIGURE 5 is a fragmentary longitudinal sectional view of a containeraccording to a modified embodiment of the present invention taken online 55 in FIG. 14;

FIGURE 6 is a fragmentary cross-sectional view taken on line 66 in FlG.3 illustrating a preferred wall conruction on an enlarged scale;

FIGURE 7 is a fragmentary longitudinal sectional view illustrating adetail of FIG. 5 on an enlarged scale;

F'iGURE 8 is an axial sectional view showing a detail of FIG. 1 andillustrating coupling means for coupling the container to the tugboat;

FIGURE 9 is a sectional View illustrating a propelling and rudder meansas used in the arrangement of FIG- URE 10;

FIGURE 10 is a side elevation illustrating a train of floating tanks, atugboat, and propelling and rudder means as shown in FIG. 9;

FIGURE 11 is a side elevation illustrating a train of floating tankswhich are operated in submerged condition;

FIGURE 12. is a side elevation of a submerged floating tank;

FIGURE 13 is a cross-sectional view taken on line 13 -13 and showing thetank in a raised floating position; and

lGURE 14 is a cross-sectional view taken on line 14-44 in FIG. 5 andshowing the floating tank provided with butfer means.

Referring now to the drawing, the embodiment of the present invention asillustrated in FIGURE 1 is a floating tank which comprises four closedcontainer cells 1, 2, 3, 4 which are towed by a tugboat 12. Eachcontainer cell has walls made of a flexible artificial syntheticmaterial which is resistant against chemical action by the transportedliquids, and also resistant against the action of salt water, light andatmospheric conditions. Synthetic resins are suitable, for examplepolyethylene, poiyisobutylene, polyvinylchloride, polyamide,polytrethalate, polytetrafluoroethylene, silcone resins, and syntheticrubber, such as butadrene rubbers.

The cell walls may consist of one or several layers of such materials,and are advantageously provided with fabric reinforcements which mayconsist of synthetic material or of organic substances. The layers maybe made of different materials, for example the inner layers are made ofmaterials resistant against the transported liquid and the outer layer,or layers, may be resistant against salt water and mechanical impacts.

The walls of the container cells are dimensioned in accordance with thevolume and intended use of the floating tank, and the wall thickness maybe a few milli-' meters. The cell walls may be made by pressing,blowing, or injection molding, or may be made of several pieces whichare connected by fusion, or by an adhesive connection to form a closedcell.

Each cell is provided with .an opening 6 for supply and discharge of thetransported liquid. A safety valve 7 is preferably provided on eachcontainer cell. The leading foremost container cell 1 has a bow-shapedforward end in order to facilitate passage through water.

The container cells 1, 2, 3, 4 are connected to each other by a netmeans which is formed by longitudinal cables 16 and transverse annularcables 17. The transverse cables 17 connect the longitudinal cables 16and resist transverse forces which develop when the contents of thecontainer cells expand. The longitudinal cables 16 are connected to endmembers 8 which have eyes to which the tow cable is connected. it isevident that the tensile forces which develop during towing, are takenup by the end member and by the longitudinal cables 16. The details ofthe construction are best seen 1n FIG- URE 3.

In the arrangement of FIGURE 1 the net means 16, 17 envelops the entirecontainer means, that is all container cells, and the container cells1-4 are arranged end to end in longitudinal direction of the floatingtank and abut on their transverse end walls 1 which form bull'- heads inthe container means. However, it is also possible to provide a net meansfor each container cell, and in this event the net means of adjacentcontainer cells are connected to each other by shackles.

FIGURE 2 shows a modified arrangement in which two container cells areenveloped by a net means, whereas another container cell 4' is envelopedby a separate net means 16, 17 having end members 8, the leading endmember 8 being connected by a cable 11 to the trailing end member 8 ofthe leading container cells 1 and 2. The cables of the net means areeither made of steel wire, or are ropes made of synthetic material. Itis also contemplated to use steel wire cables 16, 17 having an envelopeof synthetic material 116 as shown in FIG. 2a in cross-section. As bestseen in FIGURE 3, the cables .16 and 17 may be connected to each otherby knots 18.

In the embodiment of FIGURES 4 and 4a, a transverse set of containercells a to g is arranged side-by-side, and enveloped by an outer casing15 consisting of a flexible material to form container cells 1 to 4.Each inner cell a to g has at one end thereof an opening 26a for loadingand unloading which is closed when the cell is filled. The outer casing15 is also shown in FIGURE 3. It will be understood that each of thecells 1, 2, 3, 4 can e constructed in accordance with FIGURE 4 andinclude a set of container cells a to g. The uppermost cell a is notused for the transported liquid, but is filled with air so that thecontainer means is raised higher above the water line 14. Thecross-section of the smaller cells a to g is chosen is such a mannerthat the outer walls of the cells form a continuous surface which isengaged by the casing 15. As shown in FIG. 4a, a hose 12%) connects eachopening 20a with the opening 6 in the outer casing 15 so that containercells b to g can be filled with a liquid, and air cell a can be filledwith air.

In the event that in the cells b to g excess pressure develops, the aircell a is compressed so that air escapes through the safety valve 7.This arrangement prevents excess stress on the walls of the cells, or onthe casing 15.

FIGURE illustrates a modified embodiment in which the container is notsubdivided and the casing 15 con stitutes the cell wall. A containercell 21 is provided within the larger cell, and is filled with .air. Asafety valve 7 connects the interior of the air cell 27. to theatmosphere. As described above, excess pressure in the large containercell which may be created by mechanical impact or by development by gasfrom the transported liquid, will compress the air cell 21 whichequalizes the pressure by discharging air through the safety valve 7.

FIGURE 6 illustrates container cells b and c having walls 2%. Thearrangement corresponds to the construction of FIGURE 4, but the casingwall 15 is provided with an inner lining 22, which, for example,consists of synthetic foam and which has such a consistency as to enterand close leaks occurring in the wall of the casing. This effect issimilar to the known construction of automobile tires. Each of the cellwalls 28 is preferably provided with a corresponding leak filling liningof gummy substance 29' particularly when no outer casing 15 is provided,and the container cells are directly 'LTr veloped by the net means 16,17.

FIGURE 7 shows cables 16 connected to an end memher 8 which is providedwith an eye 36 for the tow cable. Bolts 37 detachably connect the cables16 to the end member 8 and engage threaded portions 19 of the endmember. FIGURES 1 and 2 show a tow cable consisting of two parts whichare connected by a coupling means 9. The forward part of the tow cableis attached to the tugboat 12 by means of a hook 13. The coupling meansa" is shown in detail in FIGURE 8. The eye 36 of the end member 8 isconnected to the coupling means 9 by a rod 39 which is pivotallyconnected at 33 to a coupling part 43. A corresponding coupling part 43'is attached by an eye 38' to the tow cable 11. Coupling parts 43 and 43'have flanges 44 and 44- respectively, and are connected to each other bya connecting member 42. The flanges 44 and 44 limit longitudinalmovement of the coupling members 43 and 43', but permit relative turningof the same in the connecting member 42. Consequently, the floating tankcan roll without twisting the towing cable 11. The body of the couplingmeans 9 is made of a light material so that the coupling means 9 floatsfor example, the body of the coupling means 9 may be made of a syntheticfoam material. A signal mast 1G is attached to the body of the couplingmeans and carries signal lamps as shown in FIGURES l and 2. An electricconductor 46 is connected to a source of electric power located on thetugboat 12, and is attached to the tow cable 11 by rings 49. Awater-tight electric coupling connection 47 connects the conductor 46 tothe conductor 48 which is connected to the signal lamps 10 on the mast16, and a conductor passes from the electric coupling 47 through thehollow coupling part 43 to the end flange 44'. The end flange 44 ofcoupling member 43 is also connected to a conductor 40 which passesthrough the hollow coupling part 43 and has a portion 41 on the floatingtank. The end flanges 44 and 44' are in sliding engagement with contactmeans which permit the current to pass from the tugboat to the floatingtank although the two coupling parts may turn relative to each otherduring rolling motions of the floating tank. The conductor 49, 41supplies current to signal lamps 41' on the floating tank. As will bedescribed hereinafter, remote controlled elements are preferablyassociated with the floating tank, and such elements are supplied withelectric current by the conductor 40, 41.

For example, FIGURE 10 illustrates a train of floating tanks includingthe two tanks 64 and 65. The leading tank 65 is connected by a tow cable11 and coupling means 9 to the tugboat 12. A propelling and rudder means50 is connected by cables to the floating tanks 64 and 65. Thepropelling means 50' and the rudder thereof is remotely controlled fromthe tugboat 12 and supplied with electric current through an electriccable as described above. The propelling force of the propelling means59' relieve the tow cable 11 so that the tensile stress in the same isreduced.

FIGURE 11 illustrates a similar arrangement in which the floating tanks64 and 65 are directly connected by a cable, and in which the propellingand rudder means is placed between the leading floating tank and thetugboat. In this arrangement, the tugboat does not tow the floatingtanks, but serves only as a station from which electric power isprovided to the propelling means 50. An electric cable 63 connects thetugboat with the propelling means 50. It will be noted that in thearrangement of FIGURE 11, the floating tanks are submerged which can beproduced by suitable ballast in one of the container cells, or byattaching heavy ballast elements 67 to the acearia floating tanks asdescribed below with reference to FIGS. 12 and 13. This arrangement hasthe advantage that high waves cannot pound the floating tanks in a heavysea. The electric cable connection 63 can be so slack that the tugboatcan follow all movements of the waves on the water surface, whereas thefloating tanks 64 follow a continuous path. The extent of submersion canbe controlled by suitable means on the tugboat and on the floatingtanks, as will be described hereinafter.

FIGURE 9 illustrates the construction of a propelling and rudder means.The outer body 50 is water-tight and floats. Connecting members 51 and52 are attached to the body 50 and have eyes for connection to towcables in a manner illustrated in FIGURES l and 11. A propeller 56 ismounted on a propeller shaft '57 which is driven from a motor 59 throughtransmission gears 58. The electric conductor 61 connects motor 59 withthe electric coupling 62 which is connected by an electric conductor 63to the source of current on the tugboat 12 as shown in FIGURE 11. Therudder 53 is turnably mounted on a shaft 54 and controlled by anoperating means 55 through suitable transmission means schematicallyindicated at 55. Operating means 55 is electrically operated andsupplied with electric current through an electric conductor. 60 whichis also connected to the electric coupling 62. A horizontal flap '53 isturnable about a shaft 54 and is operated by an operating means 551connected to flap 53 by suitable transmission means schematicallyindicated at SS'a which is remotely controlled from the tugboat toeffect downward or upward movement of the propelling means 50 for thepurpose of submerging or surfacing the floating tanks 64 and 65.

FIGURE 12 illustrates a floating tank in submerged condition, which isconnected by a cable 71 to a buoy 73. Ballast means 67 are attached tothe transverse cables 17 of the net which envelops the container means66. The ballast means is so arranged that the container is held insubmerged condition, and in the illustrated position. A container 68 forcompressed air is also secured to the floating tank, and is connected toa valve 69 which is remotely controlled. An air hose 70 connects valve69 with the container cell which contains air as is described withreference to FIGURE 4 so that upon operation of valve 69 the air cell isinflated. The cable means 71 include a conductor which is connected tothe remotely controlled valve 69, and such conductor is either directlyconnected to suitable control means on a boat, or to an antenna 74 onthe buoy '73. Electrical control impulses may be transmitted from acontrol boat to the antenna 74 for operating the valve 69. When thevalve 69 is opened, the respective container cell is inflated, and thefloating tank rises to the surfaces of the water. The ballast element 67is preferably a closed container filled with sand, and is advantageouslyprovided with a discharge valve 67 which is remotely controlled in thesame manner as disclosed by the reference to the air valve 69. The airvalve 69 can also be remotely controlled to permit discharge from theinflated air cell whereby submerizing of the floating tank is obtained.

FIGURE 13 illustrates the floating tank in raised position, .and clearlyshows the air cell 21. It will be understood that although a floatingtank of the type illustrated in FIGURE is shown in FIGURES l2 and 13, itis also possible to use container means of the typ shown in FIGURES land 4 and provided with a lining as shown in FIGURE 6, in thearrangement of FIGURES i2 and 13 in which the inflating of the air cellis remotely controlled, and which the discharge of ballast may beremotely controlled.

FIGURE 14 shows a container of the type shown in FIGURE 5 incross-section. In order to prevent damage to the flexible walls of thecontainer means when the same is thrown against a pier, elongated buffermeans 76 are secured to the floating tank and extend along the sidesthereof for the entire length of the floating tank.

6 Similar buifer elements 75 are preferably provided at the bottom ofthe floating tank in order to prevent damage to the tank when the sameengages the bottom of the sea in submerged condition. The bufferelements 75 may also serve as ballast if made of suitable heavymaterial.

The floating tanks according to the present invention are particularlywell adapted for the transportation of oil and liquid fuels which havespecific density of about 0.8. Floating tanks loaded with such liquidwill be 80 percent submerged and will project with about 20 percent ofits volume above the water surface since the static pressure in thecontatiner means depends only on the height of the liquid above thewater surface, the pressure in the container means is relatively lowpermitting the use of cozrpara-tively thin material for the walls of thecontainer cells. The shape of the floating tanks will *be designed inaccordance with hydrodynamic requirements, and an elongated shape asshown in the drawings or a torpedo shape has been found advantageous. Itis evident that the shape and draft of the floating tanks will bedesigned in accordance with the type of waterways the floating tanks areto be used. Certain constructions will be more advantageous for theocean, and other constructions will be chosen for inland Waters.

While the net means 16 and 17 is illustrated to envelop the containermeans, it will be understood that it can be embedded into the outercasing 15, or in a further casing which envelops the casing 15.

. Due to the fact that the floating tanks of the present invention areflexible, they are much easier navigated than rigid tankers. Theflexible tanks give under the impact of waves, and locally producedexcess pressure i equalized by the air cells as described above, withoutany damage being caused to the walls of the container cells and to thecasing.

The casing 15 is also flexible, so that it acts as a buffer for thecontainer cells enveloped thereby.

A particular advantage of the floating tanks according to the presentinvention resides in that they can be separated from the tugboat for thepurposes of loading and unloading, while during such loading andunloading time, the tugboat is available for further trips. Since thetugboat does not have to stand by, slow working pumps can be used forloading and unloading, and empty containers can be either towed incollapsed condition with the air .cells partly filled, or can becompletely collapsed and transported aboard the tugboat.

The weight of the container means is less than 1 percent of the weightof the total load, which of course is highly advantageous. Furthermore,the floating tanks according to the present invention do not requirepumps mounted thereon as is the case with towed tanker boats.

It will be understood that the synthetic material of the container wallsis not only flexible but also elastic. Consequently sudden increase inpressure, as may occur durmg acceleration from start or by suddenimpacts, are taken up by the container walls. The net means envelopingthe contatiner means prevents excess stress on a single point of thecontainer walls.

It will be understood that each of the elements described above, or twoor more together, may also find a useful application in other types offloating tanks differmg from the types described above.

While the invention has been illustrated and described as embodied in afloating tank including a plurality of container cells having flexiblewalls, it is not intended to be limited to the details shown, sincevarious modifications and structural changes may be made withoutdepigilting in any way from the spirit of the present inven- W1thoutfurther analysis, the foregoing will so fully reveal the gist of thepresent invention that others can by applying current knowledge readilyadapt it for various applications without omitting features that, fromthe standpoint of prior art, fairly constitute essential characteristicsof the generic or specific aspects of this invention and, therefore,such adaptations should and are intended to be comprehended within themeaning and range of equivalence of the following cl ims.

What is claimed as new and desired to be secured by Letters Patent is:

l. Floating tank for transporting liquid on waterways and comprising, incombination, container means including a plurality of elongated cellsarranged in end-to-end relationship, each cell including a plurality ofclosed container cells having flexible walls, each container cell havingan opening for supply and discharge; and flexible net means envelopingsaid container means and having a portion adapted to be connected to atugboat.

L. Floating tank for transportng liquid on waterways and comprising, incombination, container means including a plurality of elongated cellsarranged in end-to-end relationship, each cell including a plurality ofclosed container cells having flexible walls, each container cell havingan opening for supply and discharge, one of said container cells beingadapted to contain air; means for supplying air to said one containercell and for discharging air from the same; and flexible net meansenveloping said container means and having a portion adapted to beconnected to a tugboat.

3. Floating tank comprising, in combination, a plurality of elongatedcontainer cells arranged side-by-side and having flexible Walls, one ofsaid container cells being adapted to contain air, and the othercontainer cells having openings for receiving and discharging a liquid;means for supplying air to said one container cell and for dischargingair from the same; and flexible means including a flexible casingenveloping said container cel s and having an inner lining of asubstance adapted to close leaks in the wall of said casing, and netmeans enveloping said casing and having a portion adapted to beconnected to a tugboat.

4. Floating tank for transporting liquid on waterways and comprising, incombination, container means including a plurality of closed containercells having flexible walls, each container cell having an opening forsupply and discharge, one of said container cells being adapted tocontain air; means for supplying air to said one container cell and fordischarging air from the same; flexible net means enveloping saidcontainer means; a tow cable having two parts respectively attached tosaid net means and adapted to be attached to a tugboat; and couplingmeans connecting said parts of said tow cables and including twocoupling parts turnable relative to each other and respectivelyconnected to said parts of said tow cables to permit rolling movementsof said container means.

5. A floating tank as set forth in claim 4 and including electricalconductor means supported on said tow cable, on said coupling means andon said container means, said conductor means being connected to saidmeans for supplying and discharging air so that the same can be operatedfrom the tugboat, said electric conductor means 'rcluding slide contactsand stationary contacts cooperating with said slide contacts, said slidecontacts being respectively mounted on said coupling parts to maintainelectrical connection during rolling movements of said container means.

6. Floating tank for transporting liquid on waterways comprising, incombination, elongated container means including a plurality ofelongated closed container cells arranged side-by-side, said containercells having flexible walls consisting of a synthetic material andincluding an inner lining of a substance adapted to close leaks in saidwalls, each container having an opening for supply and discharge, one ofsaid container cells being filled with air and having a safety valve;means for controlling the supply of air to said one container cell; aflexible casing enveloping said container cells and having a flexiblewall consisting of a synthetic material and having an inner lining of asubstance adapted to close leaks in said wall of said casing; ballastmeans attached to said casing; net means enveloping said casing and saidcontainer cells in the same, said net means including a set oftransversely spaced cables extending in longitudinal direction of saidcontainer means, annular transverse cables connecting said longitudinalcables, and end members located at the ends of said container means andattached to the ends of said longitudinal cables, one of said endmembers being adapted to be attached to a tugboat.

7. Floating tank for transporting liquid on waterways comprising, incombination, elongated container means including a plurality ofelongated closed container cells arranged side-by-side, said containercells having flexible walls, each container having an opening for supplyand discharge, one of said container cells being filled with air andhaving a safety valve; means for controlling the supply of air to saidone container cell; a flexible casing enveloping said container cellsand having a flexible wall; net means enveloping said casing and saidcontainer cells in the same, said net means including end memberslocated at the ends of said container means, one of said end membersbeing adapted to be attached to a tugboat.

8. A flexible tank for transporting liquid on waterways, comprising, incombination, an elongated closed cover casing made of a flexiblematerial; a plurality of individual container cells having walls made ofa flexible material, each container cell having means for the supply anddischarge of fluid, said container cells being located in said closedcover casing, at least one container cell being adapted to contain airand extending substantially along the length of said casing and pullingmeans attached to said cover casing and including means located at atleast one end of said elongated cover casing and adapted to be connectedto a towing means.

9. A flexible tank for transporting liquid on waterways, comprising, incombination, an elongated closed cover casing made of a flexiblematerial; a plurality of individual elongated container cells havingwalls made of a flexible material, each container cell having means forthe supply and discharge of a transported liquid, said container cellsbeing located in and confined by said closed cover casing in a positionextending in longitudinal direction of said cover casing and abuttingeach other and the inner surface of said closed cover casing; elongatedcontainer means adapted to contain air, said container means beinglocated in said closed cover casing and extending in longitudinaldirection of said cover casing; and flexible means attached to saidcover casing and including means located at at least one end of saidelongated cover casing and adapted to be connected to a towing means.

10. A flexible tank for transporting liquid on waterways, comprising, incombination, an elongated closed cover casing made of a flexiblematerial; a plurality of individual container cells having walls made ofa flexible material, each container cell having means for the supply anddischarge of a transported liquid, said container cells being located insaid closed cover casing; elongated container means adapted to containair, said container means being located in said closed cover casing andextending in longitudinal direction of the same; means for controllingthe supply of air to said container means; and flexible net meansenveloping said cover casing and including a plurality of elongatedflexible elements extending longitudinally along said elongated closedcover casing transversely spaced from each other about the periphery ofsaid cover casing, and end members respectively located at the ends ofsaid cover casing secured to said elongated flexible elements, at leastone of said end members being adapted to be connected to a towing means.

11. A floating tank as set forth in claim 10 and including a pluralityof buffer means spaced from each other around the outer surface of saidcontainer means and being located outwardly of said flexible net means.

t2. A flexible tank for transporting liquid on waterways, comprising, incombination, an elongated closed cover casing made of a flexiblematerial; a plurality of individual elongated container cells arrangedside by side and having walls made of a flexible material, eachcontainer cell having means for the supply and discharge of atransported liquid, said container cells being located in said closedcover casing and extending in longitudinal direction of the same;elongated container means adapted to contain air, said container meansbeing sated in said closed cover casing and extending in longitudinaldirection of the same; means for controlling the supply of air to saidcontainer means; and flexible net means enevloping said cover casing andincluding a plurality of elongated flexible elements extending ton'gitudinally along said elongated closed cover casing transverselyspaced from each other about the periphery of said cover casing, and endmembers respectively located at the ends of said cover casing secured tosaid elongated flexible elements, at least one of said end members beingadapted to be connected to a towing means.

13-. A flexible tank tor transporting liquid on Waterways, comprising,in combination, an elongated closed cover casing made of a flexiblematerial; a plurality of individual elongated container cells arrangedside by side and having walls made of a flexible material, eachcontainer cell having means for the supply and discharge of atransported liquid, said container cells being located in and confinedby said closed cover casing in a position abutting each other and theinner surface of said closed cover casing and extending in longitudinaldirection of the same; elongated container means adapted to contain air,said container means being located in said closed cover casing abuttingthe inner surface of said cover casing and adjacent container cells andextending in longitudinal direction of the same; means for controllingthe supply of air to said container means; and flexible net meansenveloping said cover casing and including a plurality of elongatedflexible elements extending longitudinally along said elongated closedcover casing transversely spaced from each other about the periphery ofsaid cover casing, and end members respectively located at the ends ofsaid cover casing secured to said elongated flexible elements, at leastone of said end members being adapted to be connected to a towing means.

14. A flexible tank for transporting liquid on Waterways, comprising, incombination, an elongated cover casing made of a flexible material andincluding a wall having an inner lining of a substance adapted to closeleaks in said wall; a plurality of container cells having walls made ofa flexible material, each container cell having an opening for thesupply and discharge of a transported liquid, said container cells beinglocated in said cover casing; and an elongated container cell adapted tocontain air and being located in said elongated cover casing andextending in longitudinal direction in the upper part of the same.

15. A flexible tank for transporting liquid on waterways as set forth inclaim 10 and including ballast means suspended from said casing; andremotely controlled means operatively connected to said ballast meansfor effecting discharge of ballast.

16. A flexible tank for transporting liquid on waterways comprising, incombination, an elongated cover casing made of a flexible material; aplurality of container cells having Walls made of a flexible material,each container cell having an opening for the supply and discharge of atransported liquid, said container cells being located in said covercasing; an elongated container cell adapted to contain air and beinglocated in said elongated cover casing and extending in longitudinaldirection in the upper part of the same; and a i0 plurality of elongatedbutter means supported on the outside of said casing and extending inlongitudinal direetion of the same, said buffer means being adapted toserve as ballast. f v

17. A flexible tank for transporting liquid on 'waterways, comprising,in combination, an elongated cover casing made of a flexible material; aplurality of container cells having walls made of a flexible material,each container cell having an opening for the supply and discharge of atransported liquid, said container cells being located in said covercasing; an elongated container cell adapted to contain air and beinglocated in said elongated cover casing and extending in longitudinaldirection in the upper part of the same; net means enveloping saidcasing and including a plurality of transversely spaced longitudinallyextending elements, and end members at the ends of said casing andrespectively connecting the ends of said longitudinal elements of saidnet means; and a coupling means having a first part connected to one ofsaid end members and a second part adapted to be connected to towingmeans for the tank, said first and second parts being turnable relativeto each other.

18-. A flexible tank for transporting liquid on water'- ways,comprising, in combination, an elongated cover casing made of a flexiblematerial; a plurality of container cells having walls made of a flexiblematerial, each container cell having an opening for the supply anddischarge 05 a transported liquid, said container cells being located insaid cover casing; an elongated container cell adapted to contain airand being located in said elongated cover casing and extending inlongitudinal direction in the upper part of the same; net meansenveloping said casing and including a plurality of transversely spacedlongitudinally extending elements, and end members at the ends of saidcasing and respectively connecting the ends of said longitudinalelements of said net means; and a floating means connected to one ofsaid end members and including a rudder means and propelling means, andhaving remotely controlled means for operating said rudder means andsaid propelling means.

19. A flexible tank for transporting liquid on waterways, comprising, incombination, an elongated cover casing made of a flexible material; aplurality of container cells having walls made of a flexible material,each container cell having an opening for the supply and discharge of atransported liquid, said container cells being located in said covercasing; an elongated container cell adapted to contain air and beinglocated in said elongated cover casing and extending in longitudinaldirection in the upper part of the same; and net means enveloping saidcasing, said net means being made of steel wire cables having anenvelope of a synthetic material.

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